Characteristic On Volatile Components Forming During Fermentation Process Of Soybean Paste

Soybean paste is very popular because it is rich in nutrients and it tastes unique and wonderful. Miso flavor is one of the most important factors which affect the quality of soybean paste. It is fairly valuable and important both in theory and in practice to analyze miso flavor to find out what its main volatile components are and how these components occur during the fermentation process, which can supply a science base to selection of the row fermentation materials, optimization of the fermentation process and improvement of the flavor of the products.ⅠSelection and optimization of the methods to extract volatile flavor components of soybean pasteGC-MS technique was used on distillation and extraction (SDE), solvent extraction (SE) and solid phase micro extraction (SPME) extraction of three methods for analysis of volatile components identified comparison. Three samples were prepared by GC-MS analysis of 64 species were detected volatile organic compounds, including SDE volatile substances of high boiling point lower aldehydes and alcohols test result is good, detect 16 kinds of volatile organic compounds; SE of acids and alcohols have better detection, detection of 28 kinds of volatile organic compounds; the SPME method is conducive to extraction of volatile compounds, especially low boiling point volatile esters and aldehydes, detected 38 volatile compounds. Using Plackett-Burman design and response surface analysis of soy sauce flavor extraction conditions were optimized. Optimized extraction conditions were extraction temperature 56℃, extraction time, 42min, the inorganic salt matrix addition of 0.98g. Under the optimum conditions the total peak area increased 10.18%.ⅡAnalysis of the main volatile components of the soybean pasteHeadspace SPME extraction of volatile compounds in soy sauce by gas chromatography - olfactometry (GC-O) technical evaluation of its sensory sniffing. After a soy sauce GC-O rating, from 30 kinds of volatile components identified 13 volatile compounds and flavor of the correspondence, including esters, phenyl ethanol, benzaldehyde, phenyl acetaldehyde, 2-ethyl -6 - dimethyl pyrazine, maltol, and 2,6 - dimethoxy phenol on obvious contribution to the flavor of miso.ⅢEffects of raw materials on volatile components of soybean pasteBy headspace solid-phase mass spectrometry technique (HS-SPME-GC-MS) combined with amino acid analyzer, adding different degrees of gluten flour and flavor of different varieties of soybean were analyzed, and further analysis amino acids with the typical soy flavor relationship. When you add flour, soy sauce flavor has relatively high primary flavor.Adding a low-gluten flour is conducive to the taste of soy sauce. In the production of different varieties soybean paste, we found Xiaogan soybean (XG-01) and Wuhan summer soybean (HN-01) is better in the miso flavor, and the amount of flavor is relatively high. Different varieties of soybeans on the amino acid composition and content of amino acids during the fermentation process, we found that the typical flavor compounds 1,2-dimethoxy-phenol is generated by the reaction of phenylalanine with carbohydrates.ⅣEffects on processing conditions on volatile components of soybean pasteUsing headspace solid phase microextraction (HS-SPME) and adsorption (GC-MS), combined with sensory evaluation and physical and chemical indicators, volatile components were analysed different temperatures (35,40,45,50 and 55℃) and different salt concentrations (7,10,13 and 16% )under the conditions of environmental gradients . Fermentation temperature of 45 is best and 45℃for brewing soy sauce has highest content of amino nitrogen; in the salt concentration13% of the fermentation, soy bean has highest content of amino nitrogen, and the best flavor.ⅤDynamic analysis on how volatile components occur during the fermentation process of soybean pasteUsing with HS-SPME and GC-MS in the point of processing the process volatile flavor compounds of soybean paste were determined and analyzed in the various stages of processing. The composition of volatile flavor compounds always changes in the types and relative content. Composition of volatile flavor compounds during the processing changed greatly, but also is more complex. However, the overall trend shows that pre-flavor content is less with thick beany flavor; mid-flavor were all greatly improved, with soft bean flavor and a touch of sauce slightly; in the end all kinds of flavor changes are not balanced, in particular higher alcohols and esters.